The addition of radiotherapy (RT) to androgen deprivation therapy (ADT) appears to boost overall survival in men with metastatic prostate cancer. However, it is more common for men to receive ADT alone than ADT plus RT.
“In this large contemporary analysis, men receiving prostate RT plus ADT lived substantially longer than men treated with ADT alone,” noted Dr. Chad Rusthoven of the University of Colorado, Aurora, and his associates (J Clin Oncol. 2016 June doi: 10.1200/JCO.2016.67.4788).
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Investigators reviewed the National Cancer Data Base and identified 6,382 men with metastatic prostate cancer who received ADT as first-line therapy. Of those men, 5,844 (91.6%) received ADT alone, and the remaining 538 (8.4%) men received ADT plus prostate RT. The median age of the study population was 69, 75% were white, the most common T stage was T2, N0 was the most common N stage, and 6% of the entire cohort received chemotherapy. The median follow-up time was 5.1 years, and the median time from diagnosis to initiation of RT was 101 days. Patients were excluded from the study if they died within a month of diagnosis or if they were receiving prostatectomy, cryotherapy, or brachytherapy.
Among men receiving ADT plus RT, 48% were on Medicare and 41% were privately insured. Among men receiving ADT alone, 56% were on Medicare and 27% were privately insured.
Univariate analysis revealed that, compared with ADT alone, RT plus ADT was associated with longer median overall survival (29 vs. 53 months) as well as improved 3-year (43% vs. 62%), 5-year (25% vs. 49%), and 8-year (13% vs. 33%) overall survival estimates.
Multivariate analysis also found an independent association between the addition of radiotherapy with improved overall survival (HR, 0.624; 95% confidence interval, 0.551-0.706; P less than .001). In addition, RT to the prostate only and RT to the prostate and pelvis were both associated with longer overall survival times compared with ADT alone.
The funding source for this study was not listed. Six investigators reported serving in advisory roles for, receiving honoraria or financial compensation from, or holding patents in accordance with multiple companies.
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